The present invention relates to a color photographic light-sensitive material containing a photographic coupler, and more particularly a novel development inhibitor releasing coupler capable of releasing a development inhibitor upon the reaction with the oxidation product of a developing agent (hereinafter referred to as a DIR coupler).
It is well known that, by the color development of a silver halide color photographic light-sensitive material, an oxidized aromatic primary amine type color developing agent is reacted with a coupler to form a dye, such as an indophenol, an indoaniline, an indamine, an azomethine, a phenoxazine, a phenazine, and the like, thus forming a color image. In this type, the subtractive color process is ordinarily used for color reproduction, i.e., silver halide emulsions selectively sensitive to blue, green, and red light, and yellow, magenta, and cyan color image forming materials which are respectively present therein form the complementary color thereof. For example, a coupler of the acylacetanilide or dibenzoylmethane type is used for forming a yellow color image; a coupler of the pyrazolone, pyrazolobenzimidazole, cyanoacetophenone or indazolone type is used for forming a magenta color image; and a coupler of the phenol type, such as a phenol or a naphthol, is used for forming a cyan color image.
The color photographic light-sensitive material is usually developed by one of two main processes, i.e., a coupler-in-developer type process in which a coupler is employed to add to a developing agent and a coupler-incorporated type process in which a coupler is employed to incorporate into each light-sensitive layer of the light-sensitive material so as to maintain its independent function. In the latter process, a coupler for forming a color image is added to a silver halide emulsion. A coupler to be added to a silver halide emulsion is required to render the coupler non-diffusible (diffusion resistant) in a binder matrix of the emulsion.
It is also known that a compound capable of releasing a development inhibitor depending on the density of the image during development is incorporated into a photographic light-sensitive material. In general, such a type of compound is reacted with the oxidation product of a color developing agent to release a development inhibitor. As a typical example, the so-called DIR coupler has been known in which a group having a development inhibiting function when released from the active position is introduced at the coupling position of the coupler. Examples of the DIR couplers include the compounds as described in U.S. Pat. Nos. 3,227,554, 3,701,783, 3,615,506, 3,617,291, etc., and the further improved compounds are described in Japanese Patent Publication No. 34933/80. The DIR couplers are used for the purpose of improving the sharpness of a color image due to the edge effects and the color reproducibility due to the interlayer effects, etc., as well known from the description of the above described patents.
These known DIR couplers are efficient to a certain extent. However, it has been desired to further improve their properties. In particular, known DIR couplers have the disadvantage that development inhibitor which is released during the color development diffuses from the light-sensitive material into a processing solution and accumulates in the processing solution, which, as the result, exhibits a development inhibiting function. This results in finding it difficult to constantly obtain a determined gradation in a method in which a large amount of light-sensitive materials are processed continuously, for example, in a conventional processing method commercially carried out. Thus, the contamination of processing solution arising from the development inhibitors released from the DIR couplers has been a serious problem.
In order to overcome this problem, expedient counterplans have been conducted but these have some disadvantages, and thus a satisfactory solution to this problem has not been known. For instance, there is a method in which the amount of DIR coupler employed is restricted, a method in which a color developing solution is frequently exchanged with a fresh color developing solution, a method in which development inhibitor diffusing out from the light-sensitive layer is captured by a fine grain emulsion layer which is additionally provided in the light-sensitive material, and the like. However, these method are accompanied with disadvantages in which the improvement in photographic properties due to the DIR couplers decreases, in that the cost increases remarkably, and the like.
Further, DIR couplers having an ethoxycarbonyl-substituted-2-benzotriazolyl group are known as described in U.S. Pat. No. 3,617,291. However, these DIR couplers have an unsatisfactory decomposition speed and improvement in this respect is desired.